Musical instrument



Oct. 6, 1953 e. BARR MUSICAL INSTRUMENT 3 Sheets-,Sheet 1 Filed May 2,1949 I I INVENER eor e an '5 I W M W M ATT Oct. 6, 1953 G. BARR MUSICALINSTRUMENT Filed May 2, 1949 3 Sheets-Sheet 2 [IE-1mm Oct. 6, 1953 BARR2,654,283

MUSICAL INSTRUMENT Filed May 2, 1949 5 Sheets-Sheet 3 INVENTOR e H5 y076 Ba; I

ATTUR Patented Oct. 6, 1953 MUSICAL INSTRUMENT George Barr, New York, N.Y., assignor to Arthur V. Smith, New York, N. Y.

Application May 2, 1949, Serial No. 90,811

18 Claims. 1

This invention relates to musical instruments and more particularly tothat type thereof commonly known as string instruments in which groupsof strings under relative tension, according to the laws of harmony,constitute the media whereby tonal vibrations are developed during aplaying period.

Thi invention has for its object the provision of novel musica1instruments including novel means whereby individual musical notes orgroups of such notes, constituting chords, may be changed to therebyvary the same in pitch and in musical character without interruption ofthe current playing by the performer.

This invention contemplates particularly the provision of a novelinstrument of the string type including novel mechanisms whereby thetension of the strings individually, or in selected groups, may bevaried at will to thereby produce diiferent musical tones and differentchords without interference with the current playing by the performerand to selectively produce, at will, full chord combinations known inmusical parlance as major chords, minor chords, seventh chords,diminished chords and other such combination of tones.

In place of the usual method of adjusting the tension of each stringseparately for raising or lowering its pitch to change the instrumenttuning, in accordance with the present invention, the pitch of some orall of the strings is changed simultaneously by a simple mechanism. Byemploying the present invention it is possible to change the tone of anyselected number of strings and thereby automatically to change thetuning by merely moving a tune-changing shift handle through a fixedangle. The present application covers improvements in a tuning mechanismthe principles of which were first described in my earlier applications,Serial No. 315,949, filed January 27, 1940, and Serial No. 373,087,filed January 11, 1941, both of which were abandoned, and is acontinuation-in-part of my copending application Serial No. 598,523,filed June 9, 1945, which issued May 3, 1949 as Patent No. 2,468,726.

This invention comprehends the use of a plurality of cam-like membersadapted to change the tension of certain strings in the instrument atwill. In the present application it is illustrated as employed insteel-guitar-type stringed musical instruments, for example, the typecom-' monly referred to as the Hawaiian steel guitars; and it isillustrated by two such instruments, each employing eight steel strings,in one of which four tuning changes may be produced, and in the otherthree.

Ordinarily a steel guitar player must be able to change the tuning ofhis instrument accurately and within a short interval of time betweenselections. Frequently a single selection may require several changes intuning in the course of playing a single piece and such change in tuningmust of necessity be made instantaneously. This instantaneous shiftingof tunings is practically impossible on an ordinary guitar. However, byemploying the present invention, the tuning may be changed instantly bythe musician regardless of hi skill and without interrupting or causinga pause in his playing.

Therefore, one of the purposes of this invention is to provide meanswhereby anyone may shift tunings as rapidly and accurately as a skilledmusician. Further, if the characteristic tones of any particular tuningor chord are easily perceptible to an individual, while the notes ofanother tuning are diflicult for him to distinguish,

' the player may tune his instrument to the particular tuning or chordhe is most familiar with and then mechanically shift or change to any ofthe remainin tunings. In that Way the device has an educational valuefor, if a student could recognize the tones of one of the tunings butnot of the others, he could tune the instrument in the known tuning butat the same time be sure of the proper notes after shifting to othertunings for studying their tones.

"A further object of the proposed device is to provide an improved meanof mechanically changing the tension of a string without the usualexcessive wear. This is accomplished by means of novel tuning levers androllers. A further object of this invention is to provide a fasteningpoint for the end of the strings as close as possible to the effectivepivot of the tuning lever. The purpose of fastening the strings at sucha point is to reduce the relative travel of the string along the rolleras the roller is raised and lowered for changing the tension on thestrings.

Other objects and advantage of the present invention will appear fromthe description hereinafter and the features of novelty will be pointedout in the appended claims.

In the accompanying drawings, which illustrate examples of the inventionwithout defining its limits:

Figure 1 is a perspective view of a stringed musical instrument, aneight string steel guitar, incorporating one embodiment of the novelmechanism of the present invention;

Figure 2 is an enlarged plan view of the novel tune-changing portion ofthe instrument of Figure 1; I

Figure 3 and 4 are sections of this tunechanging mechanism taken onlines 33 and 4-4, respectively, of Figure 2;

Figure 5 is an elevation of the novel string bridge structure of thismechanism taken on line 55 of Figure 3;

Figure 6 is a perspective view of a portion of another eight stringguitar incorporating another embodiment of the present invention;

Figure 7 is a longitudinal section of the mechanism shown in Figure 6;

Figure 8 is a lateral section thereof taken on line 88 of Figure 7;

Figures 9, 10, l1 and 12 are enlarged; sideelevations of the tuning camsof the tune-changin mechanism of Figure 6;

Figure 13 is a plan view of a-tuning lever and roller thereof; and

Figure 14 is an elevation of the roller portion oi t e level: o F ur 3-In the d a n s; he n v tu es ve been. lu ra n ui a y e instrume ts, butt is t h u qod' tha hese llustrat d ex mp es are not intended to definethe limits of the invention which is applicable to many'diflerent. o m os ng instruments.

The. stringed musical instrument shown in Figure l is. an eight stringsteel guitar come prising a base member {of solid wood, or. of h r uitabe mate ial, sha ed n t e ma er shown in this drawing for the convenienceof the player and the appearance. of the instrument T is as memberarries a fretbQ mo nte ac oss the. n th e i- Guitar strin s of suitabletype extend between the usual stringtightening'posts or machine heads,generally indicated' at l2, and the novel string tune-changing mechanismo the present invention mounted at the other end of the base 2 andgenerally indicated at 14, therebetween passing over two bridgespositioned beyond either end of the. fret board and generally indicatedat 8 and ill. The. bridge 8 may be any table, bridge such, for: example,a the rooved, r und a arran em nt sh wn i the. d aw nghe her and. in; acordanc wi h h n s nt invention the brid e. I0; is anov el bridgestructure in, which an indi-. vidual; o ler is provided under. each trinto support the string and at thefsame time permit, it to, movelongitudinally in, response to operat eh. o the uhe,.-.c in mec anism 4without. ca s ng, ex essive wear on. he s r and a so to, ins re at; thet e bet en the string nd he bridg does not, pe mit the st s. fromassuming ts desired tension. s. det m e by he Se ti f; he. tuhe-changinmechanism 1., This nQVel. bridge, I0 willbe described in greaterdeta l hre hefter..,

arm rest 16 is provided at one; side; of; the base 2 to support theplayersarm when playingand an electrical pickup, unit L8 is provided;Ull ler, the stringsfi, to translate thetonal vibrations thereof to;electrical signals which can be amplified, and reproduced through anelectronic amplifier and loudspeaker system, all in accord,- ance. withthe; usual practice ininstrl ments-of h e. e ase 2 may hesupported ensin able legs 20.

Re r ng to Figu es; 3 a d e tu ee an nsme h nism om ris 2 p ter i e sideframe members 22- and 24 0f: metal, or other, suitable material, held:parallel spaced rela-* tionship by two cross frame members 216 and zawhich are fastened; to the side frame-members22 and 24 as by screws orother suitable means (not shown). The cross frame member 28 is slottedat 30 (see Figure 2) at points correspond ing to the end positions ofeach string 8 to serve as an anchor for one end thereof in the mannercustomary in the tail-piece of a guitar. The other cross frame member 26serves as an anchor for adjustable counterbalancing spring mecha nisms,as will be hereinafter described. The tune-changing mechanism i4 isfastened to the guitar body 2 in any suitable manner, as by means ofwood screws 3| passing through side members, 22 and 24. A rotatableshaft 32 extends between the two side frame members 22 and 24. Thisshaft carries a cam-like structure 34; having theccross-section similartoa segment of a gear, as shown in Figures 3 and 4. This member may beformed of a solid piece of metal, plastic, or; other suitable material;or it may be made up in laminated fashion of a plurality of cam elementsof similar cross-section, one being provided for each string to betuned.Each cam, element of the cam structure 34. is, provided with four capscrews, 35. threaded into the cam around the, periphery thereof undereach string; ta be tuned and between the teeth-like portions thereof, ascan best be seen in Figure 3. Ov.er-. lying these screws; 36 aroundthe'periphery of the/cam structure 34 extends a plurality, of strips 494of pliable metal such. as brass, copper or the like, held in place on vthe surface of cam element. by suitable, means, such as screws 42; Thesestrips. lll. are provided with, a series o f holes 38, one above each ofthe screws 36,, sothat a; tool can be inserted therethrough to turn eachof the screwsriifi to" adjust it to the position desired. I

A second rotatable; shaft 44- also extends; be;-v tween the side framemembers 22 and 24 nearthe upper edge thereof, and a plurality of tune--qhanging; levers 48; are rotatably mounted thereonas shown in Figures 2;and 3; Each of these. levers- 46; comprises two plate-like s e mbers;

48 a d; 53: s F g r 21) h ld paral paced.

he at o s n by; sp cin i e 5.2- herethmugh;

on either side of the shaft 44. Each lever carries;

a r tatab e gr ov d: r l r o pulley 5. rotatably mounted between theside; members; 48; and. 50: at. one; end of lever: 46, and a second;rollen 56. hav ng a smq h surface rotatabl mounted; b tween; he o er 5and shaft 4.4 and so: posh tioned that it is. adapted toroll over the.suriace:

at; the, flexible member; above the adjustable: screws Ciga -threadedinto; the, cam iucture 34 bunge -changinglever= is provided; foreach ofthe: strings; E; to be; tuned. Each such string passes from n an h r:in: th ss; frame member 28;.

over thaggcovedroHBB-Efi Qntthe lever 55, thence over the roller bridge;l il; to the; other bridge 8? and; then to the; machine heads as shownFigures 1; and 3. The; other end of. each lever 46; remote} from011621301131 54'; carries a cross bar- 5&- to whichis attached one endof: a tension springfilh The othe end of; each; tension. spring-= BIL issecured to. one end; of; a long screw 62" which passes freely throughahole in the cross irame-memberzh ahdi s-heldintplace-by a-nut tit whichis threaded thereon on the under side of this; member 26 W fiheearrhhmeht just described, the angnlar positionof; each of: the levers isdeter-- mined by thepositionintowhichits; screws 36 are adj usted-, anditishetldin this positionby pressure of thaguitarrstring 6 passing overthe top-of the' pulley 54., In. Glider that this string pressure is notso great as to make it difiicult for the rollers 56 to move over thesurfaceof the thin metal strips 40 surmounting the screws 36, the nut 64may be adjusted to increase the tension on the spring 60 so as tocounterbalance as much of the force of the strings 6 on rollers 54 as isdesired to produce a sufficiently small residual pressure of the rollers56 on the cam structure 34 to permit easy movement of the latter inchanging tunings.

In order to insure that the cam member 34 stops in its predeterminedposition when changing from one tuning to another, a detent arrangementis provided, as shown in Figure 4, to insure the accurate positioning ofthe cam structure 34. In one end element of the cam structure 34 theadjustment screws 36 are omitted. A short lever member 66, similar inconstruction to the tunechanging levers 46, is pivoted on the shaft 44and carries a pressure roller 68 which is adapted to roll over thegear-like surface of this last element of the cam structure 34. Thedepressions in the surface of this portion of the cam structure 34 andthe diameter of the pressure roller 68 are so chosen that the rollerdrops part way into the depressions thereof and thus holds the camstructure 34 in its adjusted position. A tension spring I0 is providedto supply a force to bias this detent arm 66 toward the cam structure34. One end of this tension spring 10 is attached to the free end of thelever 66, and its other end is attached to one end of a long screw I2which passes through the cross frame member 28 and is secured there bymeans of a knurled thumbnut I4 so that the tension of spring I0 can beadjusted as desired to provide the required amount of pressure for thisdetent structure.

In a space corresponding to that occupied by the detent mechanism justdescribed but at the other end of the cam structure 34, a tune-changinglever 16 is provided extending radially from the cam structure 34.Motion of this lever 18 from one detent position to another moves thecam structure 34 so that one row of adjustment screws 36 or another ispositioned immediately beneath their corresponding pressure rollers 56.

With the novel mechanism above-described, it is readily apparent thateach of the screws 36 can be adjusted, with a tool introduced throughthe holes 38 in the strips 40, so that each of the strings 6 can be setat any desired tension, i. e.

pitch, for each of the four possible positions of r the cam structure34. The settings of the screws 36 determine the positions of thetune-changing levers 46 which, in turn, determine the position of thegrooved string-contacting rollers 54, and each thereby determines thetension on its associated string. Hence, by this novel arrangement, aplayer by setting each of the adjusting screws 36to the proper position,can tune the guitar so that each of its 8 strings will vibrate at adesired pitch and so that this pitch can be changed from one value toanother in any desired order as the cam structure is rotated from one ofits positions to another by means of its tune-shifting lever 16.

From the above-described operation of this novel tune-changing mechanismit is clear that the strings 6 undergo some longitudinal movement overthe bridge III as their tension is changed from one value to the otherby the tension-changing device I4. A pointed out above, in order toprevent the strings from being worn by this longitudinal movement at thepoint where they touch the bridge I0 in sliding contact, and toinsurethat friction at these contacting points does not prevent the stringsfrom reaching their desired values of tension, a novel bridge structureis provided. As shown in Figures 2, 3 and 5, this bridge structurecomprises a base member 18 provided with a series of crosswise slots inwhich a plurality Of grooved rollers 82 are adapted to be rotatablymounted on a shaft 84 which lies in a groove 86 extending across theupper surface of the base member I8.

A second embodiment of my invention is shown in Figures 6 through 14. Inthis embodiment, the device is contained in a square frame II2 which ismounted in the end of a steel guitar II I Fig. 6. The strings III fastenat one end in the slot I 44 of clip I43 and extended across the rollersII 6 and bridge II8 whereby they fasten to the neck portion of theguitar, the latter not being shown.

The tuning device including a series of cams (four as employed herein)I20, I2I, I22, and I23, keyed to cam shaft I24 by key I42. The shaft I24is rotatably supported at its ends in the frame II2. Means for rotatingsaid cams for changing from one tuning to another is provided by theshifting handle I26 which is fastened to the spring detent collar I25.The collar I25 is keyed to shaft I24 by ke I42 and is provided with a.cylindrical hole I40 in the side of th collar I25 adjacent the frameII2. A round nosed pin I21 is positioned in said hole I 40 and adaptedto slide therein. Said pin I21 is backed by a spring I 45 which urges itto the left (Fig. 8) into engagement with three keepers or sockets I inthe frame II2. Said sockets I4I are located at angles corresponding tothe angles between the points I28 and I39 inclusive on the cams. In thisapplication the angle between tuning points is shown as forty-fivedegrees (Fig. 10) although any prac tical angle may be used. Thereforethe shifting of cams by moving the handle I26 through the angle offorty-five degrees to another position or tuning, moves pin I2'I' intoengagement with one of the sockets I4I corresponding to the other set oftuning points located diametrically opposite said socket I M. The springforces the pin I 21 into the keeper socket I 4| which retains the camsin the new position until such time as a further change in tuning isdesired.

Between the frame H2 and the bridge II8, strings III ride in annulargrooves I45 of rollers II6. Said annular grooves I45 are provided formaintaining the guitar strings correctly positioned on the rollers.strings might move axially on the surface of the roller whereby a changein tuning would result from the variation in tension of the strings.Each roller H6 is mounted on a shaft H9 at the end of a lever I I3. Saidlever is pivoted at the opposite end by pin II4 to clip 43 which in turnis fastened to frame I I 2. The lever is also provided with a shoeportion II5 which is adapted to ride on the surface of its cam as afollower. The purpose of the above improvement is to provide a devicefor preventing wear and breakage of the string which occurs frequentlywhen the strings ride directly on the cams. I43 is provided for thepurpose of holding the end of the string. It was positioned in clip I43merely because that was the most convenient position for fastening thestring as near to the pivot point I I4 of the tuning lever II3 aspossible. If it were practical, it would be desirable to fasten thestring directly on the pivot pin I I 4 itself. The object of placing theslot or any means for holding the end of the string near to the pin H4or pivot point of tuning lever I I3 is to limit the dis-' tance rollerII6 will travel along the strings III during a change in key. By such alimitation Without the grocye, the

The slot I44 in clip I the right (clockwise in Fig 7-).

a es-ease amount; or Wear reduced: to; amin-imunn 'llhezmllen-honsing i,l4 8 .isprovidediwithzaashoelil adapted tor rideaomthe tuning came asthe: direct iollowerr This shoe [4:55 is: preferably: made of: a:setter. metal; than theacamsso; as to: allow the shoeto wearzin;plaeeaotthecams;

In order to explain the operatiomoizthisiemieof; the; present invention;i the; applicant has. illustratedat guitar. equippedlwith .means for QQQV-iding: the. tunings; of; lit-7131i;v A;v and: Eeti-th.v If. the:musician is-i-more familiar with: the tones.

the; stringsthe: tuning of EL -7thhe: would" fiBStShlfiE-thfihfilldlfi;t2fi=tortheextremeileft (Fig; andttune theistringeof; thezguitarin'the'; usual; manner; The: tuningotEflth requires thezeight: strings;to; betuned; respectively to, E,. Ff-sharp, (i-sharp, D; E; G-sharp; Beand: E. reading; from left. to righti (Fig. 8%.. With: the; handle:12am. position: shown in Fig; 7:- for: the tuning: of Ee'Tth thethirdfourth; sixthandseventh strings; (leftto right Fig; a); will; have beenIalSBdLlIIL- directly lay-points 138;,133; I36 andal39respec'rtinelggeofi the camswhich DTOdHCESTHOtGSQGTShaTD;i D, fit-sharpandsB: Since the-first; second; fiftha and eig htln strings; arenotcoupled. with; tuning: cams the; tonesi-E F-sharp; and E3 to; whichthese r espective; strings were originally. tunedare notefiectedfbvthezdevice and therefore remainthe sameotonein all. threetunings-a The theory upomwhich thisidevice is-des-igned iszthat a stringisraisedor lowered in; tone in proportion to; the number-0f unitsof.radial distance said string is" movedaway fromor. toward-theiaxis of thecam: rollers llfithemusiciarr now; desires-:tdplay in: the-tuning; of; A(netesa E, F sharp, A; C-sharp E; A,. G; sharp =and- E) he next: shiftsthehandle I 261-110 Inorder to start the-handle1 moving; it: lSi firstnecessary to over:-

onmetheresistanceeof; the-means for: holding: the

camststeadspimany, selected position. This hold" mg means-includesathepin l Zl'which is positioned,- imthe; crylind-ricalv hole I49 in collarI25 Saiol v spring I46 and is adapted-.toventeriany'oneofgthe threeoup;sockets; I41 inflame-H24. Whenrthe handle, l 26: reaches a: verticalposition the tip; of: pin. l2]:- isspositioneda for enteringthe centralor: intermediate socket Ml. This corresponds: tot theatuning; of Aand.cam points 12:9, [Big-ita andl38r.

Thus theshifting of the.:handle= we: to the: vertical position i wouldrota-tethe; came through: the'same angle .4-5; degrees as; illustrated)and theshoes ll-5:- ot the? cam levers I I3 would i be: positionedrespectively; on-icamtpointsi295 r32; L35; and I389 Thiseshift wouldproduce the-enotesim. Cs-sharmA, and .C-sharp, In the tuning; of-E-7ththese Same stringswere tuned; to, (Er-sharp; D Cit-sharp andB;Therefore thelthirdistring;;fr0m1 the: leits hasbeen. raised one-halftone, namely: from- G-sharn-to- A. By reference. tor-cam; I26EiQF-BritTWlH' bB noted that point. [29 lS:-fl11th6I from the axis: ofthe'camand shaft l-24wthan -.is point; l-3fl.- Thei'increaseof this'distanoebyvoner nnit;,raisess;the:sh0e H 5 and roller [1!firasthezcamr. is -rotated;E whereby the, tension of the: string; is:increased sufiiciently for: raising; its time; from: GV-sharp to. inIf.it were:mcreasedftwe-units;the: string would? heraisedaapproximately: ones-full;

tonez,

' lmtheireversezmanrrerthe fourthzstrings from; thesleft': has: droppedone half tone: from D to C-sharp since: the cam point I B'Z' iS' nearertos e. axisthan'point lfiiii The-sixth string-from tne and-isi'rithstringsitakes place"; inishiftingi from". the

tuning: of" A'- to; E-rfitht This. change: in; tone; accomplished in. amanner: similar to? that:- plainedi above. However it: should: benotedithati the fdurtin and seventh strings; remain: the: same:

. tonesimbotlrkeys; (AanduE-fithiz. Thisiisizeasilw aeeomplished.bysproviding aacam'surfaoe between the'points-vim the form: of a: truecircle Whereirn the radii |=2 fi-l 312 and: l'24;-| 3B are. equal: and;thereforetlie seventh: stringz is-tsnot efieetetl rotatingathe cam.

String; I41: Fig; '2'; iszrepresentative of the post! tion of that:portioniofw therstringf extendirrg tween: the: bridge li:l'8'-: arrdf.fastening. points: 01 frame H 2 andfnot conpled with tuning cams;

3 four strings. coupled with tuning: camsextend? from the bridge l'l 8to the rollers LIB-,tdttie M ll:- in clips I435 andtorm. a slight angl-eats they passoverthe saidtrnllersz- Asth'e rollers are raised: hy= the:camsithe' levers H 3' and also? section of string extending betweenrollers H6" and slot: l 44*,SWiIIg approximatelyabout'thesame? point;Therefore no: relative motion: between: thestring 'andtheProHer isset upin said rotation:

Therefore by fastening the string to the lever pivot andeliminating"theinrelative travel} the: wear: ofthe; string is greatlyreduced; This is self? evident if you consider pivoting-the levers onthed'eft of F the frame- I P2" (Fi'gq 7) and fastening the string: tothe right side: as sliown Fig. 7;

Then: as the roller is swung about" its pivot its are": of traveli willI diverge from'the are of travel ot' the-originail point 'of 'contactof"the string with the" roller;

However, although: no relative travel results rollers and strings in anareuatepathabout theircomm'om pivot' as-pointed out" ahove, there is-'=arelative travel' wliiclr would we'ar the strin'gs if'it were' n'ot forthe rollers. This travel caus me wear fr'om whitli the rellersareprovided dtreto "their cli'an'g-e in 1 length as the" tension creases ordecreases:

With-a devicesimilarto the one illustrated and d'eseribediirthisembodiment, only three the chemical tuning changes =canbemade'; but isdOEES- I-I'Oli in any-way liin-itthe number of 'manua tunihgcl-iangesp0ssibl As a; matter otfaet; the shifting lever may b'e' planedill-any position and the guitar tuned' in the samemanner as an ordi naryguitarto any-"tuning: to which the guitar coul'd have been tnned beforethe invention was installed- Although Y the appI-ioat-Jinn desorildesmal'lls" for making-tliree meehanieal changesin tunings; as pointed outabove;- the invention is notlimited w that number; Tlie number of tuningpoints (m the cams -may heincreased to -provide any praie tieal' numnerof me'ol -ianical tnning changes-d e siredi Atthe sam'e'time bystandardizing theshaft l w and camsi ill to 1-23} a musici'ancouldpurchase a set of F cams for any standard'lcomhik nation of timingchangesz some combinationsmight require tone-ohanges -on' all eightstrin'gs in whicli caseeight cams-wouldBeirequired: Ii say fiveorsixrdifierent tuningsi are also required? Q then each cam must be providedwith five or six tuning points.

Although the present invention has been described as embodied in twodifferent guitar constructions, it is to be understood thatmodifications and variations may be resorted to without departing fromthe spirit and scope of the invention as those skilled in the art willreadily understand. Thus, for instance, the novel features are capableof embodiment in many different types of stringed musical instruments.Such variations and modifications are considered to be within thepurview and scope of the following claims.

I claim:

1. A device for changing the tuning of a multi- 'ple string steel guitarincluding, a cam shaft, a plurality of cams keyed to said shaft, one camtor each string to be tuned, each cam having at least three operatingcam positions each corresponding to a tuning position for said device, atuning lever cooperating with each cam and pivoted at one end, eachlever provided with a shoe portion made of a softer material than saidcams and adapted to ride on said cams as followers for taking thefrictional wear in place of the cam, a roller mounted in the free end ofeach tuning lever for providing antifriction rolling support for eachstring, the operating tension of said strings being applied to saidtuning levers in a direction toward said cams normally to hold saidlevers in engagement with said cams, an annular groove in each rollerfor maintaining the guitar strings accurately positioned on saidrollers, a fastening point for each guitar string located approximatelyat the pivot point of said timing levers, a collar keyed to said camshaft, a shifting lever fastened to said collar for retating said camsand changing the tuning of said guitar, and a socket means incombination with a spring actuated pin for indicating and temporarilholding said cams at predetermined tuning points in the arcs ofrotation.

2. A device for changing the tuning of a multiple string steel guitarincluding, a cam shaft, a plurality of cams keyed to said shaft, one camfor each string to be tuned, each cam having at least three operatingcam positions each corresponding to a tuning position for said device, atuning lever cooperating with each cam and pivoted at one end, a rollermounted in the free end of each tuning lever for providing antifrictionrolling support for each string, the operating tension of said stringsbeing applied to said tuning levers in a direction toward said camsnormally to hold said levers in engagement with said. cams, an annulargroove in each roller for maintaining the guitar strings accuratelypositioned on said rollers, a fastening point for each guitar stringlocated approximately at the pivot point of said tuning levers, a collarkeyed to said cam shaft, a shifting lever fastened to said collar forrotating said cams and changing the tuning of said guitar, and a socketmeans in combination with a spring actuated pin for indicating andtemporarily holding said came at predetermined tuning points in the arcsof rotation.

3. A' device for changing the tuning of a multiple string steel guitarincluding, a cam shaft, apluralit of cams keyed to said shaft, one camfor each string to be tuned, each cam having at least three operatingcam positions each corresponding to a tuning position for said device, atuning lever cooperating with each cam and pivoted at one end, a rollermounted in the free end of each tuning lever for providing antifrictionrolling support for each string, the operating tension of said stringsbeing applied to said tuning levers in a direction toward said camsnormally to hold said levers in engagement with said cams, a fasteningpoint for each guitar string located approximately at the pivot point ofsaid tuning levers, a collar keyed to said cam shaft, a shifting leverfastened to said collar for rotating said cams and changing the tuningof said guitar, and a socket means in combination with a spring actuatedpin for indicating and temporarily holding said cams at predeterminedtuning points in the arcs of rotation.

4. A device for changing the tuning of a multiple string steel guitarincluding, a cam shaft, a plurality of cams keyed to said shaft, one camfor each string to be tuned, each cam having at least three operatingcam positions each corresponding to a tuning position for said device, atuning lever cooperating with each cam and piv oted at one end, a rollermounted in the free end of each tuning lever for providing antifrictionrolling support for each string, the operating tension of said stringsbeing applied to said tuning levers in a direction toward said camsnormally to hold said levers in engagement with said cams, a fasteningpoint for each guitar string located approximately at the pivot point ofsaid tuning levers, and means for rotating the cams to any selectedtuning position, in combination with means for indicating and tem-'porarily holding said cams at predetermined turning points in the arcsof rotation.

5. A device for changing the tuning of a stringed instrument includingone or more cams each cam having at least three operating cam positionseach corresponding to a tuning position for said device, a pivotedtuning lever adapted to ride on each cam, said levers being pivotedapproximately at the fastening point of their respective instrumentstrings the operating tension of said strings being applied to saidtuning levers in a direction toward said cams normally to hold saidlevers in engagement with said cams, and means for rotating said cams toany selected one of said tuning positions for raising and lowering saidlevers against the normal tension of said strings to change the tensionand thereby the tone of any selected string.

6. A device for changing the tuning of a musi-. cal instrument havingmultiple strings including, in combination, a plurality of cam elementseach having at least three operating cam positions each corresponding toa tuning position for said device, a plurality of pivoted tuning leversadapted to ride on said cam elements, each of said levers carrying aguitar string, means for rotating said cams for raising and loweringsaid levers thereby to change the tension of the strings associatedtherewith, an indexing mechanism for positioning and temporarily holdingsaid cams at predetermined positions, and adjustable elements on saidcams at said positions for determining the extent of motion of saidlevers comprising,

radially positionable stops projecting through said operating positionsof said cams to coact with said tuning levers.

7. A device for changing the tuning of a musical instrument havingmultiple strings includings, in combination, a plurality of cam elementseach having at least three operating cam positions each corresponding toa tuning position for said device, a plurality of pivoted tun- 1 1insever a apted to irie -QI1 s i cam e ements, ea h o said leverscarryin -a guitar string, m ans .ior rot tin said t ams for rais ng andlower...

ins said. vle ers thereby to chan e the ten ion of th str n ass iated thewith, an indexi g mechan m Imp ion-ins and em rarilyrhold ins sa d a spred termin d po tions, and adjustabl l ments on said "cams at aid position .for d te mining the .extentofm tion-o aid levers, eolnprisin sc ewthreaded into sa sam elemen s a sa dp era ing p sit ons.

.-.A devi e f r changing the un ng of ,a mu ical nst ument hav ng mu tple trings in lusiing; in nolnbin ion, a plurality of cam lam nt a pluof pivot d tunin l vers adapted t ride n said :cam elements, each of sai"l e s carra g .a u arstring, m an for r tating said camsior rai in andl werin said levers ther by to aha-nee t e ten ion of th s ring-asociaiesi therewit anindexine me hani m t r v n s t.' .1-

. nesaid camssat p edeterm nesi ro iti ra iust: ab e element on saidearns at said transiti ns or dete min n the extent o mo on pf sa d lvers oompr sins screws t reasie into aid c m l and a strip o p iablmateria around th p riph ry of aid mam le nts .surm unt ng said adustable elem ts to r vi e smo thly contoured pathson sv flch said tuineilevers ride.-

9- Afdevice for sh neine th t ning o ,a mu time strin s eel guitaincluding, i germination, a plu ality o cam e ements. each having at leat thr e operating cam p s t on each sca responidns t a tun n p si ion fs i evice, ,a plurality of piv ed tunin levers adapte to ride n a d amel m n ea h :of said lay rs car:

crying a guitar str ng the npera ng tens on of said strings beingapplied t said'iunln Mars in a di eation t wardsai c m narrha' y 1 9 uge said tuning lev rs into engagem nt with said cams, meansiorro ating sid lem nts ior 2 raising and lower ng s id l ers o hang th te sion f anys cte tring, and te sion springs epnne ted to each 91 said ivoted l versto pr virie a force ounl e balancln th L n e2;- erted on said piv ta levrs bysai .g ,ita stri gs,

in. In a multipl st in ed musi al in tn nent, in eombination, a d vi eior ch ngi the aning I thestrings in luding, a d .a luralit ofn melements each ha in at iileast thre p rahng am positions each cor espondn t .a tuning p on for said device a plura it 9i piv ted tuning leversadapted to ride on said cam elements, each of said ievers carrying aguitar string, the operating tension ,of said strings being applied tosaid tuning levers in ;a direction toward sai cam norm t urg .saisllevers into en agem nt with said cam and mea v. r ro ating ai 9am elem-i9! ra sing and lowe ing aisi le ers t9 hange th tem sion of anyselested str ng am a bridg memher .over wh ch a d st ing sass adj cen.sa si tuni dev ce comnri ing a ba member and a roller member moun edthereon for each str ng to provide anti-.friction erollihasnp g t 911.644.9 bride-e me ber or each strin a sa d vtime chan ng device is operatedto va he ten ion in said strings.

;1 1. Aldevice according to claim 17 characterized by the fact that thefaces ot said cams are provid d w th :a plurafit o paralle smov s paallel to th :ca axi sa d groo e hailing s b: tantially parallel radi lWalls-spa e pa 13v an am unt substantially 1 51 3 1 o t e .diamatsr ofthe headset said adjusting sc ews.

.12- a device .for ehangins he tan na a mil 12 ti-ple strin steelguitar, v-iricludilng, earnbination, a cam shaft, a plurality of cams,zsecureg to saisishaf one .eamlfor sash st ing to be tuned each ha inleast three operating aam post tiQns cash corr sponding toa tun nrositionie; saidsdevice, a pivoted tuning lever c ope ating with ea h .aroller mounted ,at s me @1151 of. each tuning lever t p ovide antkfri ton roll ing .sunnort for each str n each s ing shear? ingits roll ngupnortat a operating point 0 no e to its arn so that the pe ating ens ono Mid strin s exerts pressure normally to hold aid tuning le ers intoengagement. with s id cams, and means for rotating the cams to anyselected one of more than two tuning pg itions, and an n exing mechan m.ior indrnting and tempo ari y h ding said s at "pre et rmined n ln napmts 11.1 th .Q. rotat on correspondng l p-said tun ng po itionshang ng13- ..A 9 1 1 9rinsta in 91a 1 .1 11 ip' e st i g st el guitar, incuding, n 1 110. ati n, a cam h t a ural t o ams nse. to said shaft, onecam for each stri gag fpe tuned, each having at least three operatingcam positions each corresponding to a tuning position for said device, apivotedtuning lever cooperating with each earn, a roller mounted at oneend of each tuning lever for providing anti-friction rollin; support foreach string, each string engaging its rolling support at an operating:point opposite to ;its cam so that the operating tension of saidstrings exerts pressure normally *to hold said tuning levers intoengagement with said-cams, a fastening ;point ;for each guitarstringlocated ap-; proximately at the pivot point of said tuning leversa shifting leveflfastenegto said cam shaft for rotating said earns tochange the tuning of said. guitar, and an indexing rnechanismfori-ndigating and temporarily holding said cams at p. 3 determinedtuningpoints in their arcs of rotation.

-14. A device for changing the-tuning of a1nu;1-.- ti pl e stringmusical instrument, including in combination, a cam shaft, a plura'l-ityof cam elements each having at -least three operating cam positions eachcorresponding-to a "tuning position for said device, -a plurality ofpivoted tuning levers adapted to move said strings and to be moved bysaidcam elements,-a firstro'llermounted on each of said levers throughwhich movement is imparted :to said strings by providing anti-frictionrolling support therefor, a second roller mounted on eac-h of saidlevers through which movement imparted :to said levers iby providingantisfriction rolling support therefor, each string engaging its rollingsupport at operating point opposite :to its cam so :that'the operatingtension of said strings exerts pressure normally to rheldsaid tuninglevers into engage: ment with sa doeam an means for rota nasaid camelement t 8 sai l vers an. -ha lec r s se he an saiastnnesia 2511'?determ ne i fi llfi -1 Alsisvieeia n in thertnaingni rarmn s here t zi ad ne, 01. w? ;a plurality o sam sts arms a least three peratinesqsiticns ea h co espondin to a tun n posltlon sis isaI-a plu ality o rieted unin lay rs aslantad move sai strin s an t9 bam ves y said $81 elemnts, a firstoller mounted n sash 0i sa d leve s th ugh which movemen iim art d to a st ings b p o, vi ins anti-friction oll ng s ppor herei as qhfil v. l lla mguntsdon teaehl i sa si .lerers through whic movements imnarteg to slain levers by providing anti-friction rolling supporttherefor, each string engaging its rolling support at an operating pointopposite to its cam so that the operating tension of said strings exertspressure normally to hold said tuning levers into engagement with saidcams, and an adjustable spring structure connected to each of saidlevers to exert forces thereon opposing the forces exerted thereon bythe strings whereby the pressure applied to said cam elements by saidsecond rollers may be minimized as desired.

16. A device for changing the tuning of a multistring steel guitarincluding, a cam shaft, a plurality of cams keyed to said shaft eachhaving at least three operating cam positions each corresponding to atuning position for said device, one cam for each string to be tuned, aton-- ing lever cooperating with each cam and pivoted at one end, aroller mounted in the free end of each tuning lever for providinganti-friction rolling support for each string, each string engaging itsrolling support at an operating point opposite to its cam so that theoperating tension of said strings exerts pressure normally to hold saidtuning levers in engagement with said cams, and means for rotating thecams to any selected one of said tuning positions, in combination withmeans for indicating and temporarily holding said cams at predeterminedturning points in the arcs of rotation.

17. A device for changing the tuning of a multistring steel guitarincluding, a plurality of cams each having at least three operating campositions each corresponding to a tuning position for said device, aplurality of pivoted tuning levers adapted to ride on said cams, aroller mounted on each lever for providing antifriction rolling supportfor each string, each string engaging its rolling support at anoperating point opposite to its cam so that the operating tension ofsaid strings exerts pressure normally to hold said tuning levers inengagement with said cams, and means for rotating said cams to anyselected one of said tuning positions for raising or lowering saidlevers and rollers to change the tension or tone of any selected string.

18. A device for changing the tuning of a multistring steel guitarincluding, a plurality of cams each having at least three operating campositions each corresponding to a tuning position for said device, aplurality of pivoted tuning levers adapted to ride on said cams tosupport and distort said guitar strings between their terminal anchors,the operating tension of said strings being applied to said tuninglevers in a direction toward said cams normally to hold said levers inengagement with said cams, and means for rotating said cams to anyselected one of said tuning positions for raising and lowering saidlevers against the normal tension of said strings to change the tensionand thereby the tone of any selected string.

GEORGE BAR-R.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,809,710 Kaufman et a1 June 9, 1931 2,040,633 Schulz May 12,1936 2,323,969 Biederman July 13, 1943

